LAUSR

Inherent brittleness and low heat resistance are the two major obstacles that hinder the wide applications of poly(L-lactide) (PLLA). In this study, we report a fully biobased, highly toughened and heat-resistant PLLA ternary blend, which was prepared by dynamic vulcanization of PLLA with poly(D-lactide) (PDLA) and an unsaturated bioelastomer (UBE). The results indicated that during dynamic vulcanization PDLA cocrystallized with PLLA to form stereocomplex (SC) crystallites, which not only enhanced the molecular entanglement but also accelerated the crystallization rate of PLLA matrix. With increase in the content of PDLA, the matrix molecular entanglement increased while phase-separation was enhanced, which enabled the impact strength to increase first and then decrease. The ternary blends containing 10 wt.% PDLA showed the highest impact strength. The presence of SC crystallites makes it possible to achieve a fully sustainable PLLA/VUB/PDLA ternary blend with highly crystalline matrix under conventional injection molding, due to the high nucleation efficiency of SC towards crystallization of PLLA. The highly crystalline ternary blend showed excellent heat resistance and better impact toughness than high impact polystyrene.摘要随着环境污染的加剧以及不可再生石油资源的逐渐枯竭, 生物基高分子材料受到了越来越多的关注. 聚乳酸作为一种可再生的高 分子材料, 由于具有良好的生物降解性、生物相容性和机械强度, 在众多领域都具有巨大应用潜力. 然而聚乳酸也存在一些缺陷限制着它 的应用领域, 如冲击韧性差、耐热形变温度低等. 基于此, 我们利用动态硫化技术, 将左旋聚乳酸(PLLA), 右旋聚乳酸(PDLA)以及不饱和 生物基弹性体(UBE)通过自由基引发动态硫化成功制备了冲击韧性优于高抗冲聚苯乙烯、耐热性突出的全生物基PLLA/VUB/PDLA三元 共混物, 在不降低生物质含量、不影响其降解性能的情况下, 实现了PLLA的高性能化.